Zanbil () is a small Island in the Caspian Sea off the Bay of Baku, Azerbaijan. It is also known as Duvanni Island.
The name Zanbil is Persian (òÃÂèÃÂÃÂ) and means "a big basket". The name "Duvanni" (ÃÂÃÂòðýýÃÂù), meaning "money" in Russian, is connected to Stepan Razin.
The island is part of the Baku Archipelago, located in the ÃÂlÃÂt (Alat) municipality area, which consists of the following islands: Boyuk Zira, Dash Zira, Qum Island, Zanbil, Sangi-Mugan, Chikil, Qara Su, Khara Zira, Gil, Ignat Dash and a few smaller ones.
The area of Zanbil Island is 0.4 km<sup>2</sup>. Its length is 0.9 km and its maximum width 0.5 km. Zanbil lies NW of Xara Zira and the nearest shore of the mainland is about to the SW.
There is a 25 m high mud volcano on Zanbil.